3.9=0.65(y+8)

Solution for 3.9=0.65(y+8) equation:

Simplifying
3.9 = 0.65(y + 8)

Reorder the terms:
3.9 = 0.65(8 + y)
3.9 = (8 * 0.65 + y * 0.65)
3.9 = (5.2 + 0.65y)

Solving
3.9 = 5.2 + 0.65y

Solving for variable 'y'.

Move all terms containing y to the left, all other terms to the right.

Add '-0.65y' to each side of the equation.
3.9 + -0.65y = 5.2 + 0.65y + -0.65y

Combine like terms: 0.65y + -0.65y = 0.00
3.9 + -0.65y = 5.2 + 0.00
3.9 + -0.65y = 5.2

Add '-3.9' to each side of the equation.
3.9 + -3.9 + -0.65y = 5.2 + -3.9

Combine like terms: 3.9 + -3.9 = 0.0
0.0 + -0.65y = 5.2 + -3.9
-0.65y = 5.2 + -3.9

Combine like terms: 5.2 + -3.9 = 1.3
-0.65y = 1.3

Divide each side by '-0.65'.
y = -2

Simplifying
y = -2